In an ironing or pressing process, a heated tool, such as an iron, is used to remove wrinkles from fabric. The iron may be heated to a temperature of 180-220° C., depending on the fabric. The bonds between the long-chain polymer molecules in the fibers of the fabric are loosened upon heating. While the molecules are warm or hot, the fibers are straightened by the weight of the iron. When the fabric is cooled down to room temperature, the fibers hold their straightened shape. Some fabrics, such as cotton, require the addition of water during the ironing process to loosen the intermolecular bonds.
A pressing apparatus or system includes an iron and an ironing board for pressing or smoothing clothes, sheets or other articles made from fabric material. The iron is heated before and during the use, and is generally placed vertically on the ironing board.